Sealed crusher

ABSTRACT

A gyratory crusher having a frame (1) and in the frame an eccentric shaft (3) rotatable around a vertical shaft in the frame, with a vertical inclined hole in it. A main shaft (4) is supported by bearings in the hold of the eccentric shaft, a supporting cone (5) being attached to the upper end of said main shaft (4). Around the main shaft, below the supporting cone (5) there is a sealing cover (10) covering the eccentric shaft. The upper edge (12) of the sealing cover (10) is sealed against the main shaft (4) by means of a sealing member (13), the outer edge of which has been fitted in an annular groove (17) on the inner edge (12) of the sealing cover (10). The face-to-face arranged upper and lower surfaces so the part (13&#34;) of the sealing member (13) in the groove and the groove (17) of the sealing cover (10) are inclined so that their outer edges are higher up than their inner edges.

TECHNICAL FIELD

The present invention concerns gyratory crushers. More particularly theinvention concerns sealing, by means of which the internal parts of thecrusher are protected against dust entering from outside.

BACKGROUND ART

Gyratory crushers comprise a vertical eccentric shaft with an inclinedinner hole therein. A main shaft, into which a supporting cone isattached, and which is supported to the frame at its upper part by meansof an upper supporting bearing, is mounted in the hole. The supportingcone is surrounded on its sides by the frame of the crusher, an elementacting as a wearing part called outer crushing head being attached tothe frame. An element acting as a wearing part called inner crushinghead is attached to the supporting cone. The inner and outer crushingheads, together, form a crushing chamber, where the feed material iscrushed. When the eccentric shaft is rotated, the main shaft and,together with it, the supporting cone get to an oscillating movement,whereby the gap between the inner and outer head at each point variesduring the working cycle. The smallest gap during the working cycle iscalled the setting of the crusher, and the difference between theminimum and maximum gap is called the stroke of the crusher. Through themagnitude of the setting and the stroke of the crusher, inter alia theparticle size distribution of the produced crushed material and theproduction capacity can be influenced.

Presently, a gyratory crusher can be adjusted by means of a hydraulicsystem, so that the main shaft can be moved vertically in relation tothe frame. This makes it possible to change the setting so that the sizeof the final product corresponds to the desired one and/or to maintainthe same setting when the crushing heads wear.

Dust particles and other foreign objects from the crushing chamber mustbe prevented from entering the bearings of the eccentric shaft and themain shaft, as well as the primary and secondary gear of the drivedevice, and in general the lubricant circuit inside the crusher, andthrough that the surfaces of the elements to be lubricated.

In the crushers of prior art, generally used presently, there is forthis purpose a sealing cover around the eccentric shaft and the drivedevices connected with it, attached at its lower edge to the frame, andabove it as an extension a narrower cylindrical supporting sleeve forthe sealing. For the upper edge of the supporting sleeve, there is anannular recess formed in the lower surface of the supporting cone. Theouter surface of the supporting sleeve forms a sealing surface, againstwhich a seal ring in the recess of the supporting cone is pressed. Theseal ring glides in its recess in relation to the supporting cone alonga spherical surface. In addition, when the setting of the crusher isadjusted, the seal ring glides up and down along the surface of thesupporting sleeve. The ring can also glide around the supporting sleeveagainst the surface of the sleeve.

The most essential drawback of this prior art is that the recesses andgrooves formed in the supporting cone for sealing members make thesupporting cone weaker. Other drawbacks of the prior art are thecomplicated shape of the lower surface of the supporting cone--and thushigh production costs--as well as the fast wearing of the seal ringcaused by the required great movement of the seal ring.

Because in these constructions known in the art, the sealing memberrises or lowers with the main shaft of the crusher when the verticalposition of the main shaft is adjusted, the consequence is that also itsdistance from the upper supporting bearing, that is its radius ofoscillation changes. For this reason, it has been necessary to dimensionthe sealing against the cone in this structure as a compromise betweendifferent radii of oscillation, and some clearance has been reserved toit for extreme positions.

In publication DE 673 351, there has been described a crusher, in whichthe sealing cover is sealed against the main shaft so, that the outeredge of a horizontal sealing member has been fitted in an internalrecess provided in the upper part of the sealing cover. A drawback ofthis known solution is, however, that little by little the oscillatingmovement of the main shaft causes the sealing to break, even if it ismade of flexible material. Alternatively, big clearances must be used,whereby the tightness of the construction will be lost.

In publication DE 1 243 955, there is described a crusher, in which thelower surface of the outer edge of a sealing member between the mainshaft and the sealing cover is fitted tightly against the frame of thecrusher. In case the main shaft is lifted upwards in order to change thesetting, the sealing member departs from the surface of the crusherframe.

Publication DE 1 507 573 discloses a crusher, in which the sealingmembers between the main shaft and the sealing cover are completelyunprotected from above, and thus subject to dust, whereby the surfaceswear very quickly. It is also not unambiguously clear from thepublication, how the sealing cover and the sealing member remain inposition when the setting is changed.

DISCLOSURE OF THE INVENTION

General Description

The present invention relates to a crusher.

The most essential feature of the invention is that the sealing cover issealed against the main shaft, and shaped so as not to be broken by theoscillating movement of the main shaft. The tightness will also bemaintained when the setting of the crusher is changed, because thesealing cover and the sealing member do not move in relation to theframe when the setting of the crusher is changed. Also the sealingitself is protected against dust.

A further advantage of the structure in accordance with the presentinvention is that the supporting cone can be made stronger, as there isno need to make any recess for the supporting sleeve of the sealing. Inaddition, the supporting cone is more easily manufactured. The lowersurface of the supporting cone can be even left as a cast surface, andno smooth machined surface is required on it, against which the sealingwould be fitted, as in the structures of prior art. The sealingstructure is also in other respects simpler and more economical andsecure than the known solutions.

As the sealing has been moved from the sealing sleeve inwards againstthe main shaft, the circumference of the circle where the sealing iseffected is shorter. For this reason, also the required sealing memberis smaller. Also the speed of the movement of the sealing member--andthereby the wearing of the sealing member--is reduced.

As in the solution in accordance with the invention there is always oilin the space below the sealing member, providing the lubrication of thebearings of the crusher, the same oil is also provided on the surface ofthe main shaft below the sealing member. As the main shaft, along withthe wearing of the crushing heads, as a rule must be raised, the sealingmember always receives clean oil free of dust, thus preventing thewearing of the sealing member.

In a structure in accordance with the present invention, the main shaftglides in relation to the sealing member, when the vertical position ofthe main shaft is adjusted, whereby the radius of oscillation isindependent of the position of the main shaft and always constant.Therefore the sealing member can be positioned with an optimal clearanceor even without any clearance, whereby also its sealing effect is good.

The sealing of the internal circumference of the sealing member can beimproved by placing one separate sealing or a plurality of individualsealings between the internal circumference and the main shaft. In thisway, also the wearing of the internal circumference of the sealingmember can be reduced.

In the structure in accordance with the present invention, the balancingof the crusher can also be easily provided without increasing the heightof the crusher, because in the structure in accordance with theinvention, there will be more space vacant for the counter weight. Thespace vacant below the supporting cone can be utilised, and the counterweight can be constructed correctly for every stroke.

It is also known to use compressed, in crushers to prevent dust fromentering on the sealing member and therefrom further the bearings of themachine. In the structure in accordance with the invention, it ispossible to provide the sealing cover with a channel, and bring thecompressed air directly to the sealing.

DESCRIPTION OF DRAWINGS

Enclosed drawings form a part of the description of the invention.

FIG. 1 illustrates one gyratory crusher in accordance with the presentinvention.

FIG. 2 shows an enlarged detail of the crusher of FIG. 1.

FIG. 3 shows as enlarged an alternative embodiment of the detail of FIG.1.

EXAMPLES

The main parts of the crusher of FIG. 1 are a frame 1, a transmissionmechanism 2, an eccentric shaft 3, a main shaft 4 and a supporting cone5 arranged on the main shaft.

An outer crushing head attached to the upper part of the frame 1 and aninner crushing head attached to the supporting cone 5 form a crushingchamber. To the lower part of the frame there is arranged thetransmission mechanism 2, by means of which the eccentric shaft 3 isrotated.

The lower end of the main shaft 4 is via bearings 6 supported to anadjusting piston 7 arranged at the lower part of the frame 1. By leadingpressure medium into a cylinder below the adjusting piston or from thecylinder, the main shaft can be raised or lowered in relation to theframe.

The upper end of the eccentric shaft 3 is provided with a pole ring 8with counter weights. The lower edge of the pole ring is provided with abevel gear 9.

The eccentric shaft 3 is covered with a sealing cover 10. The skirt 11of the outer edge of the sealing cover is tightly fixed to the lowerpart of the crusher frame 1. The inner edge 12 is sealed against themain shaft 4 by means of a sealing member 13. The sealing member can beshaped e.g. as shown in the drawings.

The sealing cover is dimensioned so that between the main shaft and theinner edge of the sealing cover there is left a space or a grooverequired by the sealing member.

The outer surface of the sealing cover 10 is inclined downwards andoutwards. Thus, no crushed stone is gathered upon it.

In FIG. 2, the structure of the sealing member is shown in more detail.The sealing member 13 is formed of a flangelike part 13' and of asleevelike part 13" within it, extending upwards from the inner edge ofthe flangelike part.

Against the inner circumference of the sealing member 13, there can be acylindrical protective sleeve 14 pressing tightly against the mainshaft.

The inner edge 12 of the sealing cover 10 forms an annular flange. Afixing ring 16 is arranged above the flange so that a groove 17 isformed between for the sealing member 13. The groove has a form of thesealing member, but it is sideways wider than it, so the upper and lowersurfaces of the flange part 13' of the sealing member 13 set tightlyagainst the groove, but, however, can move sideways in it along themovement of the main shaft 4.

The face to face arranged upper and lower surfaces of the groove 17 ofthe sealing cover 10 and the flangelike part 13' of the sealing memberare parts of a spherical surface, the centre of which is the centre ofthe oscillating movement of the main shaft at the upper end of the mainshaft 4.

On top of the fixing ring 16 of the sealing member there is, inaddition, a protective ring 18 made of some elastic material.

A channel 19 is formed in the sealing cover 10, the main part of whichis parallel with the cover and joins a channel 20 of the fixing ring 16,which again opens at the lower surface of the fixing ring against thesealing member 13. Through the channels 19, 20, compressed air can beblown to the sealing member from a pipe 21, for removing dust from theupper surface of the sealing member 13 gliding against the groove 17.

In addition, the sealing member 13 can be provided with one or severalseparate seal rings 22, 23 which seal the gap between the sealing memberand the main shaft or the sealing member and the protective sleeve 14.The seal ring 23 can be a changeable, elastic ring, that scrapes themain shaft when the main shaft is raised and lowered.

When the main shaft 4 is making its oscillating movement, the centre ofmass of the main shaft and the masses fastened to it changes itsposition. Therefore the masses connected with the pole ring 8 of theeccentric shaft of the crusher must be dimensioned so as to balance theforces caused by the movement of the main shaft and the centre of massof the masses connected with it, and thus decrease the swinging of thecrusher.

With different stroke movements, the path of movement of the main shaftand the centre of mass of the masses connected with it is different. Forthis reason, the position or magnitude of the masses connected with thepole ring of the eccentric shaft should be adjustable. In a structure inaccordance with the invention, more room will be left above the polering 8 and thus detachable or adjustable counter weights 24 (FIG. 1) canbe attached to the pole ring, and these counter weights can be added,removed or moved according to need in order to balance the crusher withdifferent stroke movements.

The protective ring 18 can be also replaced e.g. with a rubber bellow.This kind of a rubber bellow can extend to be tightly against theprotective sleeve 14 or the main shaft 4 itself.

FIG. 3 illustrates an alternative embodiment of the sealing arrangement.There the elastic protective ring 18 on top of the fixing ring 16 hasbeen replaced by a protective ring 25 which is attached to the sealingelement 13 so, that the lower surface of the protective ring is incontact with the protective cover. The contact surface 26 between thesealing member and the protective ring is conical or a part of aspherical surface.

Thus, the protective ring oscillating with the seal ring maintains itscontact with the fixing ring 16. The protective ring 25 is attached tothe upper surface of the sleeve part 13" of the sealing member, wherebyit properly also protects the seal ring from dust.

In the embodiments of both the FIG. 2 and FIG. 3, the upper and lowersurfaces of the sealing member 13 and the groove 17 do not necessarilyhave to be exactly spherical surfaces, but also slightly inclinedconical surfaces following closely to these kinds of spherical surfacescan be used.

Because the distance between the sealing member and the centre of theoscillating movement of the main shaft is in practice long compared withthe length of the flangelike part 13' of the sealing member, thespherical surfaces of the face to face upper and lower surfaces of thegroove 17 of the sealing cover 10 and the flangelike part 13' of thesealing member can be replaced by conical surfaces forming with thecentre axis of the crusher an angle which is smaller than 90°. It isessential that the outer surfaces of both the groove 17 of the sealingcover 10 and the flangelike part 13' of the sealing member are higher upthan their inner edges.

The sealing member can also be shaped so that there is no sleevelikepart 13" in it. Thereby the separate seal rings 22, 23 can be arrangedin a narrow area on the inner edge of the sealing member.

We claim:
 1. A gyratory crusher havinga frame; an eccentric shaftrotatable around a vertical axis in the frame, with a vertical inclinedhole therein; a main shaft supported by bearings in the hole of theeccentric shaft, said main shaft comprising an upper end extending abovethe eccentric shaft, and a supporting cone attached and supportedthereto, and arranged around the main shaft, below the supporting cone,a sealing cover covering the eccentric shaft, said sealing cover havingan inner edge, and an outer edge fastened tightly to the frame, wherebythe sealing cover is sealed against the main shaft with a sealing memberso that contact surfaces between the sealing cover and the sealingmember are formed in an annular groove and a part fitted in the groove,said groove having the shape of the part fitted in the groove, but beingsideways wider than the portion of said part fitted in said groove,wherein the contact surfaces of both said groove and the part fitted insaid groove are inclined in such a way that radially outer edges of saidgroove and the part are higher than radially inner edges of said grooveand the part.
 2. A gyratory crusher in accordance with claim 1, whereinthe groove is arranged on the inner edge of the sealing cover, and thepart is a part of the sealing member.
 3. A gyratory crusher inaccordance with claim 2, wherein the face to face arranged upper andlower surfaces of the groove and the part define annular, partialsurfaces of a sphere, a center of the sphere being a center ofoscillating movement of the main shaft at the upper end of the mainshaft.
 4. A gyratory crusher in accordance with claim 2, wherein thesealing member includes a flangelike part and a sleevelike part withinit.
 5. A gyratory crusher in accordance with claim 2, wherein the inneredge of the sealing cover is sealed against the main shaft via aprotective sleeve fitted against the main shaft.
 6. A gyratory crusherin accordance with claim 1, wherein the groove is arranged between thesealing cover and a fixing ring on top of it, and the part is a part ofthe sealing member.
 7. A gyratory crusher in accordance with claim 6,wherein the face to face arranged upper and lower surfaces of the grooveand the part define annular, partial surfaces of a sphere, a center ofthe sphere being a center of the oscillating movement of the main shaftat the upper end of the main shaft.
 8. A gyratory crusher in accordancewith claim 6, wherein the sealing member includes a flangelike part anda sleevelike part within it.
 9. A gyratory crusher in accordance withclaim 6, wherein a protective cover is arranged on top of the sealingmember and the fixing ring whereby the contact surfaces between thefixing ring and the protective cover are inclined in such a way thatradially outer edges of the fixing ring and the protective cover arehigher than radially inner edges of the fixing ring and the protectivecover.
 10. A gyratory crusher in accordance with claim 1, wherein theface to face arranged upper and lower surfaces of the groove and thepart define annular, partial surfaces of a sphere, a center of thesphere being a center of oscillating movement of the main shaft at theupper end of the main shaft.
 11. A gyratory crusher in accordance withclaim 10, wherein the sealing member includes a flangelike part and asleevelike part within it.
 12. A gyratory crusher in accordance withclaim 1, wherein the sealing member includes a flangelike part and asleevelike part within it.
 13. A gyratory crusher in accordance withclaim 1, wherein the inner edge of the sealing cover is sealed againstthe main shaft via a protective sleeve fitted against the main shaft.14. A gyratory crusher in accordance with claim 1, wherein between thesealing member and the main shaft there is at least one changeable sealring.
 15. A gyratory crusher in accordance with claim 1, wherein betweenthe sealing member and the main shaft there is a changeable elastic ringthat scrapes the main shaft when the main shaft is raised or lowered.16. A gyratory crusher in accordance with claim 1, wherein there is achannel in the sealing cover, one end of the channel joining acompressed air pipe arranged outside of a crushing chamber, and a secondend of the channel opening onto the sealing member.
 17. A gyratorycrusher in accordance with claim 16, wherein the second end of thechannel opens onto the sealing member via a channel arranged in a fixingring of the sealing member.
 18. A gyratory crusher in accordance withclaim 1, wherein a lower surface of the supporting cone includes a castsurface.
 19. A gyratory crusher in accordance with claim 1, wherein alower surface of the supporting cone is without a recess machined in itfor sealing.
 20. A gyratory crusher in accordance with claim 1, whereinone or several detachable or adjustable counter weights are attached toa pole ring on the upper end of the eccentric shaft.